From RCI:
A. What are the One-Plus-One weeks that appear in my account?
When you confirm an exchange in an area targeted for the One-Plus-One promotion, an additional vacation week at special rates is deposited into your account automatically. It appears online as a One-Plus-One week; however, it cannot be accessed online. You will need to contact an RCI Guide to confirm these. For every regular exchange confirmed into targeted areas, members may confirm an additional week into any of the same areas for $219.99 domestic (299.99 CD) and $263.99 international (362.99 CD). Availability is in the following regions:
East Coast - Virginia Beach, Virginia to Myrtle Beach, South Carolina
North Interior US - Illinois, Indiana, Ohio, West Virginia, Kentucky, Virginia
Pennsylvania
Tennessee & Smoky Mtn Resorts in North Carolina and Georgia
Canada - Ontario & Quebec
East Coast - Maine to Maryland
Great Lakes Area (Wisconsin, Michigan, Minnesota, Iowa, South Dakota)
Ozarks (Missouri, Arkansas, Oklahoma)
Texas - Inland
Southeastern Florida (Vacation Village at Bonaventure #4025 and Vacation Village at Weston #5773 only)
All International Destinations
The One-Plus-One program is not available online. You will need to contact an RCI Guide for assistance. These weeks are valid for two full years, for travel dates up to two years in advance. However, they are only valid for the areas outlined above. You do not have to confirm the same resort/area with your One-Plus-One week as you confirmed to qualify for it. And you don't have to confirm consecutive weeks. After you confirm a standard exchange in one of the targeted areas, the One-Plus-One week is deposited into your account automatically overnight. You may also confirm the extra week on the same phone call if you want - the RCI Guide can deposit it for you immediately.